1. Field of the Invention
This invention relates to a photographic operation control circuit for a camera.
2. Description of the Prior Art
In recent years the trend in the field of cameras is that various photographing functions are incorporated in cameras so as to enable fully automatic control in sequence of photographing operations such as exposure control, focal point detection, data printing and film winding up only by pushing down the release button prior to photographing. These conventional cameras, because of their employing the sequent control system in the electrical circuit form have a disadvantage that the complexity of circuitry structure is remarkably increased. Further, since the amount of consumption of electrical energy necessary to accomplish one cycle of exposure operation along with the above mentioned various portions of the camera is increased as compared with the ordinary camera, there is a high possibility of occurrence of faulty operation at a time on the way through the sequence of steps when the battery voltage falls below the satisfactory operating level. That is, as the light sensor, exposure determining means and the shutter cocking and film winding mechanism must be actuated in sequence, it is highly possible to happen that even when the battery voltage was at the satisfactory operating level before the actuation of the release button, the battery voltage is no longer satisfactory after the time of termination of the exposure control operation. In such a case, the following step of shutter cocking and film winding will be caused to stop before completing itself, thereby the camera cannot be made ready for the next exposure. The provision of so many functions in the camera gives rise to an additional problem that the mere transition from one step to another not always leads to assure the reliability and accuracy of actuation control. In more detail, taking an example of the focusing function, the initiation of an exposure before the focusing operation has been completed will result in photographs of unsharp images. On this account, the auto-focus cameras are generally provided with means responsive to the setting completion signal for permitting a transition to the subsequent step of making an exposure. In the case of a camera in which only the distance measuring operation is automatically performed, while the setting operation of the objective lens of the camera is adjusted manually, however, it is impossible to detect the completion of the actual setting of the objective lens so that when a release is actuated at a time during the focusing operation, as the exposure operation immediately follows, an image of out-of-focus will be recorded on the film. Again, with regard to the data printing function, when ever-varying data such as the time data from watch device in the digital form are selected for employment in printing, provision must be made for latching the presentation of the data for the period of actuation of the data recorder, or otherwise two or more successive different data would be recorded as overlapped one upon the other, thus ambiguous recording of data is effected. In this connection, it should be noted that as the data to be printed, it is desirable to make use of the data at the time of photographing, but not of the one occurring when the presentation of the data is latched. The camera having so many kind of function as mentioned above is required not only to display information of the exposure factors and value, but also to indicate various informations such as of a condition of in-focus and informations of data to be recorded so that the structure of the indicator is complicated.